Hemoglobin has a high absorption rate around 415 nm. That is why UV light is used in forensic science to check if a stain is blood (very dark) or not (somehow reflecting).
But this is totally useless for hunting. You cannot chase something that is not reflecting. Most of the plants and most grounds do not reflect UV so you will see nothing.
I have watched several videos about blood tracer flashlights but I am still not sure how good they work. Most video material is just too bad.
Looking at the reflectance (what you see) of blood (example figure) there are not a lot of wavelengths that blood is reflecting: Red, deep red and infrared.
Any light with a warm spectrum would be much better that a cold LED light. The warmer the better. Maybe assisted with some extra red and IR LEDs.
Using orange or red filters may be even better. They cut out all colors below 600 nm. Seeing less green should help in the forest.
This is about that moment I usually get that, “But I once saw in a movie…” response. Haha.
Honestly, I have found that following blood trails is a skill like any other when it comes to hunting…you just have to develop it over time and with practice. You start out slowly, checking every step carefully, but after awhile you know what to look for and it comes more easily. You also start to understand the way animals move when mortally wounded and can anticipate where to look.
But yeah, it would be cool to have a light that made it glow like Predator blood.
LED blood tracker lights work fine - reds/oranges really pop out, but since these use both red and blue LEDs running together, blues also pop out (not normally a problem when hunting as blue is rarely encountered).
An incandescent light with a blue filter doesn’t pop red/orange colors as much but it does not pop blues and better isolates red/orange from other colors. Red and orange filters do not work at all.
I don’t know the physics behind all of this, I have just done some very quick and simple tests to see what works and what doesn’t.
I would guess that the reason blue filters work on incandescent lights and not LEDs might have something to do with infrared. Incandescents put out a good amount of IR and LEDs hardly any.
Why a combination of blue (or green) and red LEDs are needed to work I do not know. But I do notice with LEDs red actually looks more orange than red. Apparently single LEDs can be used if they put out the right mix of blue and red light – the Bushnell tracker light that I have has 3 tracking LEDs that all appear to be the same magenta color, most others seem to use a combination of red and blue LEDs.
Nice video. How do you come up with these ideas and the time. Anyways it appears the blue/green was the best. But I probably won’t have one of those with me if ever in that situation but I will have a WW high CRI. Thanks for putting that together.
Nice test Vestureofblood! This is unique test to bust all kind of flashlight blood tracking sellers that are selling real “myth” for costumers believing that red, blue, green light does make difference while their only function is to blind you while tracing for blood trail.
If someone finds/invents flashlight that really works with blood trail it will be big hit in hunting world cause every hunter wants one in a backpack.
Until that light appears I will just stick to cool white zoomie which works the best of everything I seen or tried till now.
P.S. It gotta be zoomie?Why?
Zoomie light without any spill unlike the reflector light has very sharp borders, so there is better contrast between illuminated area and dark area. The enhanced contrast lets you perceive blood trail better and you have preserved night vision.
I think I remember seeing in one of the blood tracking threads that some lights used something like a blue light always on and a red light blinking. The occasional extra wavelength helped it jump out as the red was pulsed.
Seeing your decent results with green and red, I’m curious if that blinking action helps. If you still have the blood around, care to try something like that with the green and red? Green always on with occasional red flashes (or vice versa)? Does that help draw your attention to the blood?
I have been using Primos BloodHunter for 2 years already and it's been the best blood tracking flashlight for me. I remember I read something about it and looked into it again. Thought this might help you as well: